Arsenal put recent disappointments behind them with an old fashioned 1-0 win over Roma in the first leg of their Champions League second round tie and holders Manchester United left the San Siro with a draw after a lively 0-0. Barcelona's Thierry Henry grabbed a valuable away goal in a game the favourites could easily have lost to Lyon, while Atletico Madrid were twice pegged back by Porto.
In an open game in Milan, United began brightly and dominated the first half, with Cristiano Ronaldo particularly dangerous from two set-pieces, one of which hit the post.
The Portuguese also flashed a header just wide from Ryan Giggs’s cross as the homeside looked unusually disjointed for a Jose Mourinho team.
There was more about Inter in the second but Adriano blazed an effort wide of the mark and Edwin van der Sar somehow managed to deny Cambiasso and Zlatan Ibrahimovic.
Ji Sung Park then came agonisingly close to turning Ronaldo’s cross into the net before Giggs saw his shot blocked brilliantly by Ivan Cordoba.
Ronaldo rifled one last free-kick of the chest of Inter goalkeeper Julio Cesar with the last kick of the game and United had to settle for a point ahead of the return leg in Old Trafford.
Arsenal, too, were lively from the off and both Nicklas Bendtner and Samir Nasri could have put them ahead before van Persie was fouled by Philippe Mexes in the 37th minute and got up to smash a low spot kick past goalkeeper Doni.
The home side should have doubled their lead just five minutes after the restart but Bendtner shot over from close range before Nasri just failed to connect with a low cross as Arsenal pressed forward.
The Gunners passed up another guilt-edged chance after a mistake allowed Emmanuel Eboue through on goal, but after delaying his shot he somehow fired wide and moments later John Arne Riise shot agonisingly off target at the other end.
Barcelona have seen their lead in the Primera Liga cut from 12 points to seven in the last two games and they looked shaky at the back again as set-piece specialist Juninho deceived keeper Victor Valdes with a dipping free kick.
Barca looked clueless in the first half but they improved in the second and got the deserved equaliser through Henry's low header at the far post.
The Spanish side are now clear favourites ahead of the second leg at the Camp Nou but it could have been a lot different had Karim Benzema converted a one on one against Valdes in the first half, or had his excellent snap shot not cannoned off the post.
Lisandro Lopez scored a goal in each half to help Porto rally to a 2-2 draw in Madrid.
Atletico took the lead in the third minute when Sergio Aguero's attempted pass to strike partner Diego Forlan ran through to Maxi Rodriguez on the right of the area and he slammed the ball past goalkeeper Helton.
The equaliser came after 22 minutes when defender Pablo Ibanez badly misjudged a header and Lopez raced through to drive the ball in off Leo Franco.
A dreadful mistake by Helton gifted Atletico their second goal in first-half stoppage time. Forlan fired a speculative long-range effort and the ball squirmed through the Porto keeper's hands and into the net.
Porto fought back valiantly and thouroughly deserved the equaliser that came in the 72nd minute when Lopez turned in Aly Cissokho's low cross.
